How to mount FreeBSD 9.0 iso file writable mode?

view full story

http://unix.stackexchange.com – I want to edit bsdinstall script of freebsd 9.0 iso file. I tried to extract files,edit and recreate iso but I couldn't boot it.I realized that some of files missed while extracting. I also use tools like "ISO Master" but when I try to open it, I get this error: Failed to read directory tree: 'Rockridge filename missing when expected on image' Now I am trying to mount it and edit inside mounted directory. But I can mount it only read-only format. Is there any way to mount writable format so that I can edit it? (HowTos)